Stresses and strains induced by fetal kicks

Fetal movements are known to play a key role in prenatal skeletal development. We know this from a number of conditions in which reduced or restricted fetal movements are linked to abnormal affecting newborn babies in which the bones or joints are not properly formed. The most common example is developmental dysplasia of the hip (DDH), where the hip joint is unstable or even dislocated. Another example is arthrogryposis, where multiple joints are abnormally shaped and oriented. Despite knowing that fetal movements contribute to formation of the bones and joints, the stresses and strains induced by these movements have never before been characterised. This research aims to fill this void by creating computational models of babies kicking in utero and calculating the stresses and strains induced in the bones and joints by these kicks.

Dr Stefaan Verbruggen is the postdoctoral researcher leading the research, and the project is funded by Arthritis Research UK.

Methods

Fetal movements are automatically tracked from cine MRI scans (obtained from our collaborators at King’s College London) as shown below.

Those movements are modelled using finite element and musculoskeletal models to calculate the force generated by the kick, and the muscle forces acting. Next, the muscle forces are applied to fetal skeletal geometries, obtained from collaborators in Great Ormond Street Hospital. The methodological pipeline is shown below. Current work is assessing the stresses and strains in the skeleton over gestational age, and for different conditions which increase the risk of DDH, such as fetal breech position and reduced amniotic fluid (oligohydramnios).